In the past, computing applications such as computer games and multimedia applications used controls to allow users to manipulate game characters or other aspects of an application. Typically such controls are input using, for example, controllers, remotes, keyboards, mice, or the like. More recently, computer games and multimedia applications have begun employing cameras and software gesture recognition engines to provide a human computer interface (“HCI”). With HCI, user gestures are detected, interpreted and used to control game characters or other aspects of an application.
In conventional gaming and multimedia applications, a user's body position is often used to measure whether or not the user has performed a given gesture. In particular, the HCI system may measure the angle formed by a vector through a pair of adjacent joints relative to a reference plane, such as horizontal. That angle, by itself or together with other pose or motion information, is used to identify a gesture that the user has performed. Thus, as an example, the HCI system may measure the angle that a user's forearm (as indicated by the positions of the wrist and elbow) forms with a horizontal reference plane to identify whether a user has performed a given gesture.
The problem with such traditional methods of gesture detection is that angles formed between two adjacent end joints are subject to large amounts of jitter and noise. As such, using adjacent joints can at times be unreliable for gesture detection.